In a story called The Vanished Batman (Batman #101, August 1956), Gothamites are startled to see a Batman-less Robin taking care of crimes and emergencies on his own, and even more startled to see the Batmobile, Batplane and Bat-signal redesigned into a Robinmobile, Robinplane and Robin-signal, respectively. TV newsmen and newspaper writers begin asking the question, "Where is Batman?" Batman has gone undercover to infiltrate a mob to get the goods on a "Big Job." Said job proves to be an underwater attempt to cut through the hull of the docked ship Natonic and steal five million dollars. Batman gets word to Robin in time for the police to net the would-be thieves, and joins Robin in nabbing the gang leaders. Then the Caped Crusader makes his public reappearance, with the operation a total success.

The Robinmobile only appeared in this one story and it's hardly significant to Batman's history, let alone comics history, but for some reason I liked the idea of it and thought it would make a fun addition to my collection of Batman-related vehicles.